The application claims the priority of Japanese Patent Applications No. 2003-82181 filed on Mar. 25, 2003 which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to an imaging apparatus, and more particularly, to the imaging apparatus to be mounted on an electronic endoscope or the like and having such a configuration that a slight air gap is formed between an imaging surface of a solid-state image pickup device and a cover glass.
2. Description of the Related Art
A CCD (Charge Coupled Device) and so on which are solid-state image pickup devices are provided at an end of an electronic endoscope, for instance, so as to image the inside of an observed body and a subject. In recent years, however, miniaturization of an imaging portion including the CCD is underway in conjunction with reduction in diameter of the electronic endoscopes and miniaturization of cameras.
FIGS. 7A to 7D show a configuration of an imaging apparatus according to Japanese Patent Laid-Open No. 10-216083 which is an example in the past. As shown in FIGS. 7A and 7B, the imaging apparatus uses an imaging portion (mounting element) 4 wherein a cover glass 3 is adhered to an imaging surface S side of a CCD 1 by an adhesive b1 as if sandwiching leads 2 of a conductor. The imaging portion 4 is produced by a mass production method for performing an assembly mounting process and an inspection process of the CCD 1, leads 2 and cover glass 3 like an assembly-line operation, such as a TAB (Tape Automated Bonding) method. According to the imaging portion 4, a small air gap AG of 50 μm or so in an airtight state is formed between the imaging surface S of the CCD 1 and the cover glass 3.
The CCD 1 is placed in a through-hole 5A formed on a circuit board 5, and the leads 2 jutting out of the imaging portion 4 are connected to terminals on the circuit board 5 side. A circuit member 6 for processing an imaging signal is provided on aback side of the circuit board 5. Furthermore, as shown in FIGS. 7C and 7D, an adhesive b2 is applied to the whole area of the circumference of the cover glass 3 and is filled in the through-hole 5A, which strengthens fixing of the imaging portion 4 and the circuit board 5 and also secures airtightness of the air gap AG between the imaging surface S of the CCD 1 and the cover glass 3. Such an imaging apparatus has the imaging signal obtained by the CCD 1 supplied to an image processing circuit via a signal line connected to an i terminal of the circuit board 5, and an image of an observed body is displayed on a monitor and so on based on the signal after image processing.